The present invention relates to a communication system, and more specifically, although not exclusively, to a communication system which incorporates a plurality of communication units all of which, or selected ones of which, can be assigned a common conference call facility, therewith to enable all communication units assigned to said facility to transmit and to receive auditive messages simultaneously therebetween.
The device which interlinks the communication units of the inventive communication system preferably has the form of a physical conductor.
Respective units incorporate first means for receiving auditive information and/or second means for transmitting auditive information.
In order to utilize the conference call facility of the inventive communication system, a given number of the aforesaid communication units are allotted a group assignment and are adapted to co-act with one another in a manner to establish a conference call facility.
The invention is also based on the concept that an analog signal derived from auditive information transmitted from any one of the aforesaid units is sampled prior to being received as sampled information in a further unit, and that in dependence on the sampling contribution, the information or data derived from the sampling contribution is converted to auditive information.
Several types of communication systems of this kind are known in the art. For example, it is known to establish a conference call facility in communication systems of this kind by assigning to certain communication units a particular group status, by connecting said units to a physical conductor which is common to all units in the group, and to connect all units to this conductor during a conference call and therewith pass along the conductor an analog signal that corresponds to an overlay of the pieces of auditive information or data to be transmitted.
Thus, it is possible with such a system to transmit information simultaneously from a plurality of communication units and to receive this information simultaneously in a plurality of further communication units.
In systems such as these, a physical conductor is required for each group of units needed to establish a conference call facility.
Consequently, systems which incorporate static conductors for the purpose of interlinking the various groups of communication units are relatively inflexible, since when wishing to switch the assignment of a unit, from one group to another, or requiring a unit to serve more than one group at one and the same time, it is necessary to incorporate additional physical conductors between all units belonging to one or more groups.